Junction box for a photovoltaic solar panel

ABSTRACT

A junction box for a solar panel comprises a housing, a lid, a first connector and a second connector. The housing comprises sidewalls and a top wall defining an interior space. The first coupling comprises a first contact element and the second coupling comprises a second contact element. Said contact elements penetrate at least one of the sidewalls, so that the contact elements provide an electrical contact from external contact elements to internal contact elements, such as solder tails. Internal contact elements are arranged at least partially in said interior space. The top wall comprises an opening extending only partially in said top wall. Said opening is located such in the top wall that access to said solder tails in a substantially perpendicular direction to the surface of a solar panel for connecting the solder tail to the solar panel is provided.

FIELD OF THE INVENTION

The invention relates to a device for affixing to a photovoltaic solarpanel module in order to provide a connection between solar panelmodules of a photovoltaic array or a connection between solar panelmodules and other devices such as a bus system or cables.

PRIOR ART

Such devices are also known under the designation junction boxes orconnection boxes. Such junction boxes are well known from prior art.Usually said junction boxes provide an electrical contact betweencontacts of a photovoltaic solar panel and cables which are connected toa further photovoltaic solar panel or to any other device, such as adistribution box or a bus system

EP 1 501 157 shows an example of such a junction box. Contacts of asolar panel extend above the surface on which the junction box isarranged and protrude through openings into the interior of the junctionbox. Said contacts are received by a contact element that is arranged inthe interior of the junction box. Furthermore the junction box comprisesopenings through which cables can be inserted into the interior of thejunction box in order to be received by said contact element. Thecontact element provides an electrical contact between the contacts of asolar panel and the wire. Said junction box further comprises an openingin order to provide access to the interior of the box. The opening issealed by means of a sealing ring and a lid.

Since the solar panels are usually exposed to effects of weather such asrain, snow, wind etc. it is particularly important that the junctionboxes or connecting boxes have weatherproof properties. Suchweatherproof properties include the resistance against moisture, wateror temperature differences.

The inflow of water into the interior of such a junction box should beavoided under any circumstances, since it may cause short circuitsand/or lead to corrosion of the metallic connection elements. Thepresence of water in the interior of a junction box is not only a resultfrom water that enters through leaky portions of the junction box, butmay also be the result of water condensation. However, the presence ofwater decreases the operational reliability and the lifetime of such ajunction box.

Furthermore junction boxes are exposed to thermal differences thatresult in thermal expansion of the junction box itself Such an expansioncan lead to a malfunction of a sealing element, such as the abovementioned sealing ring.

Usually such an expansion leads to mechanical stresses which may lead tocracks in the boxes. Especially sensitive to such mechanical stressesare glued sections.

A further drawback of devices according to prior art is themanufacturing process. Still a high percentage of such a box ismanufactured by hand. This leads to high costs. Furthermore qualityissues may also arise, since precision and reliability of each craftsmanis variable.

Quite often the electrical connection of the electrical contacts betweenthe junction box and the solar panel are designed as a spring contacts.Such spring contacts are susceptible to oxidation and mechanicalinfluences. Said negative influences can lower the efficiency of a solarpanel arrangement.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a junction box, whichdoes not have the disadvantages of the junction boxes known from priorart. In particular the junction box shall be manufactured and/or appliedto a solar panel in an automatic manner, while at the same time theelectrical connection between elements of the junction box and the solarpanel shall be optimized.

This object is achieved by a junction box having the features of claim1. Accordingly a junction box for a solar panel comprises a housing, alid, a first connector or coupling and a second connector or coupling.The housing comprises sidewalls and a top wall defining an interiorspace. The first coupling comprises a first contact element and thesecond coupling comprises a second contact element. Said contactelements penetrate at least one of the sidewalls, so that the contactelements provide an electrical contact from external contact elements tointernal contact elements, such as solder tails. Internal contactelements are arranged at least partially in said interior space. The topwall comprises an opening extending only partially in said top wall.Said opening is located such in the top wall that access to said soldertails in a substantially perpendicular direction to the surface of asolar panel for connecting the solder tail to the solar panel isprovided.

Due to the specific arrangement of the opening in the top wall access tothe solder tails is being provided so that parts of a robot areintroduceable in an effective manner in order to affix the solder tailto a solar cell. The remaining parts of the top wall covers the interiorspace as much as possible. This means that the junction box according tothe present invention can be mounted in an automatic manner for examplein an assembly line.

Preferably the top wall comprises an outer sidewall that extendssubstantially perpendicular from the top wall and that surroundssubstantially the outer circumference of the top wall, so that anoverflow space is defined by the top wall and the outer sidewall.

Preferably the opening is substantially surrounded by an inner sidewallwhich extends substantially perpendicular from said top wall. Such asidewall limits the overflow space to the opening.

If the interior space is filled with a filling material excess fillingmaterial may flow into the overflow space defined by the top wall, theouter sidewall and the inner sidewall. The filling material ispreferably a potting compound (pottant) or a foam.

Preferably filling material is injectable into the interior spacethrough said opening, so that the interior space is fully filled withsaid filling material, and in that the opening is closeable with thelid. Preferably the filling material is a material that is injected in aliquid state and hardens after being injected. Preferably the fillingmaterial is a pottant or a foam.

Preferably the lid comprises a wall extending substantiallyperpendicular to the lid and having a shape that fits into the openingin the top surface.

Such a wall provides a good and easily sealable contact between theopening and the lid.

Preferably the lid comprises further embossments that are arranged suchthat they extend through the opening into the interior space when beingmounted onto the housing. Due to said further embossments fillingmaterial is forced to flow through the opening into the overflow space,when said lid is mounted onto the housing when filled fully with fillingmaterial.

Due to that overflow the lid is connected to the housing in tightlysealed manner. The embossments are advantageous, since they reduce thevolume in the interior space so that filling material and air that maybe present is forced out of the interior space. Additionally a closureforce is provided.

A method for manufacturing a junction box according to the presentinvention comprises the steps of

-   -   providing the first coupling with a first contact element and        the second coupling with a second contact element;    -   connecting the first coupling and the second coupling with the        housing;    -   providing each of the contact elements with a solder tail;    -   affixing the diode at the first contact element and at the        second contact element.

With such a method a pre-mounted junction box is provided. Said junctionbox can be mounted on a solar panel.

A method for providing a solar panel with a junction box e.g. as definedabove comprises the steps of:

-   -   Applying adhesive to the junction box base perimeter or flange;    -   arranging the junction box on a surface of a solar panel module;    -   affixing solder tail to the contacts of a solar panel;    -   filling the interior space of the housing with a filling        material; and    -   mounting the lid on the top wall, so that parts of the lid,        extend into the interior space of the housing.

Thereby the pre-assembled junction box can be mounted onto a solar panelin an effective and automatic manner. The arrangement of the openinggiving access to the solder tail is a particular advantage in terms ofautomatic manufacturing.

A solder element for providing an electrical connection between a firstelectrical device and a second electrical device comprises acylindrically shaped contact zone to be contacted to the firstelectrical device, a resilient zone and a cylindrically shaped transferzone having a solder zone to be contacted to the second electricaldevice. The axes of the contact zone and of the transfer zone areaxially arranged in alignment of a longitudinal axis. The resilient zoneenables adjustment of the axial distance between the contact zone andthe solder zone.

Such a solder element is particularly advantageous as the adjustment ofthe length enables the solder element to be used in a flexible manner.

Preferably the resilient zone is arranged between the contact zone andthe solder zone.

Preferably the resilient zone is designed as a bending structure,wherein bending of said bending structure results in said adjustment.This allows an easy adjustment of the length.

The resilient section comprises at least one, preferably at least two,even more preferably at least three to six, resilient web.

Preferably the solder element is produced by a stamping and/or formingprocess.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings will be explained in greater detail by means of adescription of an exemplary embodiment, with reference to the followingfigures:

FIG. 1 shows a perspective view of a junction box according to thepresent invention with a lid according to the present invention;

FIG. 2 shows a bottom view of the junction box of FIG. 1;

FIG. 3 shows a top view of the junction box of FIG. 1;

FIG. 4 shows a side view of the junction box of FIG. 1;

FIG. 5 a-b show a perspective view of the lid for the junction boxaccording to FIG. 1;

FIG. 6 a-b show the junction box according to FIG. 1 without a lid;

FIG. 7 a-b show a connector clement that is arranged in the junctionbox;

FIG. 8 a-b show the connector element of FIG. 7 with a coupling element;

FIG. 9 a-d show assembly steps of a junction box according to thepresent invention;

FIG. 10 a-c show views of a junction box of a further embodimentaccording to the present invention;

FIG. 11 a-d show views of a solder element and

FIGS. 12 a, b show views of a weather cover or junction box according toa further embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the drawings possible embodiments are described. Thedrawings and the description illustrate preferred embodiments and shallnot be construed to limit the invention, which is defined by the claims.

FIGS. 1 to 4 show a junction box according to the present invention.Such a junction box comprises preferably a housing 1, a lid 2, a firstcoupling 3 and a second coupling 4. The junction box according to thepresent invention is used to provide an electrical contact between asolar cell of solar panel and external contact elements such as cablesetc. or other solar cells. Such solar panels have a typical size of2.200 mm×2600 mm, but can also be smaller or larger. With such solarpanels voltages between 70 V and 500 V and currents between 0.1 amps and10 amps can be produced. However, the junction box according the presentinvention can also be used for solar panels providing higher or lowercurrents or voltages, respectively.

The housing 1 comprises sidewalls (here a first sidewall 11 and a secondsidewall 12) and a top wall 13. The sidewalk 11, 12 extend from the topwall 13. An interior space 10 is defined by said sidewalls 11, 12 andsaid top wall 13. Said interior space 10 is provided to accommodateelectrical contact elements which are in an electrical contact with asolar cell of a solar panel. When the junction box is mounted on a solarpanel the interior space 10 shall be sealed off from environmentalinfluences such as water, air etc. to prevent oxidation of theelectrical contact elements. Afterwards the terms external and internalwill be used. The term external or exterior space is to be understoodthat it comprises everything that is arranged outside of the housing 1,whereas the term internal is to be understood as to comprise everythingthat is arranged within the interior space 10.

Preferably the housing 1 is made of plastics. Preferably polycarbonate,for example Lexan 940-701, is used to provide the housing. The housing 1is preferably injection molded.

Furthermore the housing 1 in that embodiment comprises a bottom wall 14that is designed as a flange 19. Said flange 19 limits the interiorspace 10 on a side that is opposite to the top wall 13. When the housing1 is arranged in the surface of a solar panel, said bottom wall 14 orflange 19 faces the surface of the solar panel either its frontside orits backside. In the embodiment as shown, the flange 19 extendssubstantially parallel to the top wall 13 from the sidewalls 11, 12 inthe external direction. In that case actually the surface of the solarpanel limits the interior space 10, wherein the flange 19 acts as asupport element and contact element.

In order to provide the sidewalls 11, 12 with a higher stiffness, saidsidewalls 11, 12 may comprise a plurality of ribs 18. In the embodimentas shown in FIG. 1 said ribs extend on the external surfaces of thesidewalls 11, 12. Additionally or alternatively said ribs can also bearranged on the internal surfaces of the sidewalls 11, 12 that face theinterior space 10. If the sidewalls 11, 12 are already stiff enough, theribs 18 may be omitted.

The first coupling 3 and the second coupling 4 extend from the housing1. The first coupling 3 comprises a first contact element 5 and thesecond coupling 4 comprises a second contact element 6. Said contactelements 5, 6 penetrate at least one of the sidewalls. Thereby saidcontact elements 5, 6 provide an electrical contact from the externalside to the interior side or interior space 10, respectively. With otherwords an electrical contact is provided by means of said contactelements 5, 6 from an external contact element to internal contactelements. An external contact element can be for example a cable of abus system linking several solar panels. An internal contact element canbe a solder tail 7 that is arranged to contact a solder zone of a solarcell. Preferably such a solder tail 7 is arranged such that its mainparts are arranged in the interior space 10, whereas some parts extendfrom the interior space 10 to the external space (e.g. environment).

Preferably the first coupling element 3 and the second coupling element4 are made of plastics such as polycarbonate. This means that saidcoupling elements 3, 4 can be injection molded. Alternatively thehousing 1, the first coupling 3 and the second coupling 4 can be moldedin one piece.

As it can be seen from FIG. 1 the mechanical design the first coupling 3and the second coupling 4 are different. Such a coded design(male/female) has the advantage that the user does not contact a cablein a wrong coupling.

FIG. 2 shows the junction box from the bottom side. Here it can be seenthat the bottom wall 14 is designed as flange 19 that extends over thewhole length of the sidewalls 11, 12. However, the flange 19 is arrangedsuch that it does not extend into the interior space 10. Hence a bottomopening 15 is provided which is limited by the sidewalls 11, 12. In amounted state said bottom opening 15 is closed by a surface of the solarpanel. Preferably the flange 19 is glued to the surface of a solar panelby means of hot melt adhesive, such as a dow corning HM2500, which is areactive hot melt neutral cure adhesive.

The junction box according to the present invention will be placed on asurface of a solar Panel. Preferably the junction box is affixed to saidsurface by means of an adhesive. Afterwards the solder elements will beconnected to the solder zones of a solar cell. After that the junctionbox according to the present invention is mechanically and electricallyconnected to a solar panel and the interior space 10 will be filled witha filling material, such as a pottant or potting material. The fillingmaterial can also be a foam. Said filling material is insertable throughthe opening 16 that is arranged in the top wall 13. Due to the fill inof the filling material the electrical contacts will be covered by thefoam so that oxidation is prevented. Furthermore the filling materialmay have flame retardant properties. The opening 16 receives parts 20,21 of the lid 2, as they are described by means of FIG. 5. The opening16 is located such in the top wall that, when the lid is not present,access to said electrical contact elements 7 is provided. Preferablysaid access is provided in a substantially perpendicular or orthogonaldirection to the surface of a solar panel. This means that a robot in aproduction line is able to quickly contact the electrical contactelements 7 to corresponding contact zones of a solar panel. Reference ismade to FIG. 9 d where this situation is clearly visible. Due to thespecific shape of the opening 16 that provides access preferably to theelectrical contact elements 7 only, the other elements that are arrangedin the interior space 10 are protected by the remaining parts of the topwall 15. The opening 16 in the top wall 15 is preferably designed assmall as possible in order to allow access to the electrical contactelements 7 only. This means that the remaining parts of the top wall 15are as large as possible.

Preferably the pottant or filling material is a silicone rubber such asan RTV pottant. A memontive (GE) TSE3664 condensation-cure flameretardant RTV can be used. TSE 3664 is a two-component condensation curesilicone rubber (RTV).

In further embodiments it may also be possible that the flange 19extends from the sidewalls 11, 12 in direction of the interior space 10as well as in the direction to the external side. In such an embodimentthe bottom opening 15 is limited by the flange 19. However, the surfaceof the solar panel still limits the interior space 10 in the area of thebottom opening 15.

Alternatively it is also possible that the flange 19 or bottom wall 14extends from the sidewalls 11, 12 towards the interior space 10 only.Also in that embodiment the bottom wall 14 comprises a bottom opening 15through which the solder tail 7 extend to the external side. Asmentioned in the above mentioned designs, the surface of the solar panelstill limits the interior space 10 in the area of the bottom opening 15.

As it can be seen in FIG. 2 the first contact element 5 and the secondcontact element 6 extend through the sidewalls 11, 12 from the externalside or exterior space into the interior space 10 of the housing 1. Bothcontact elements 5, 6 are connected to an internal contact element 7.The internal contact element 7 is preferably a solder tail which isdescribed by means of FIG. 7. Additionally the first contact element 5is connected to the second contact element 7 by means of a diode 8. Theopening 16 is designed such that the diode can be arranged such that itis protected by the remaining parts of the top wall 13. This means thatthe diode 8 is preferably not visible from the exterior when viewed in adirection perpendicular from the top wall 13. However, in otherembodiments the diode 8 is arranged such that it is at least partlyvisible from the exterior when viewed in a direction perpendicular fromthe top wall 13. Such an arrangement is advantageous for quality checks.

Such a diode acts as a security device for bypass protection. Preferablya silicon diode rated 1000V/10 A is used.

FIG. 3 shows a top view of the junction box according to the presentinvention. This figure is mainly used to explain the angular arrangementof the first coupling 3 and the second coupling 4. A first axis 100 runsthrough the first coupling element 3 with the first contact element 5and a second axis 200 runs through the second coupling element 4 withthe second contact element 6. If a plug is connected to said first orsecond coupling elements 3, 4, it will be inserted in direction of saidaxis. Preferably the first axis 100 and the second axis 200 lie in thesame plane, which plane is parallel to the surface of a solar panel orto the bottom surface 14 or flange 19, respectively.

As it can be seen in FIG. 3 the first coupling element 3 and the secondcoupling element 4 are arranged angular with respect to each other. Withother words, the first axis 100 is angular to the second axis 200. Thisis designated in the figure by means of an angle α. Preferably angle αis between 5° and 175°. However, other angles, larger than 175° orsmaller than 5° are also possible. An angle α between 75° and 125° isparticularly preferable, since the effect of the mechanical force thatresults from the cable (external connector) onto the couplings isminimized while the junction box is mounted. This is the case when thejunction box is mounted such that the bisecting line of angle α isdirected. downwards, e.g. towards the roof of a building or the floor ofa solar power plant etc.

Alternatively the plane in which the two axis 100, 200 are arranged canalso be angular to the surface of a solar panel. This means that thefirst coupling 3 and the second coupling 4 extend oblique with respectto the top wall 13 or the bottom wall 14. This is a particular advantageif the solar panel is arranged tilted, since due to the obliquearrangement the couplings extend in a direction that is substantiallyperpendicular to the roof of building etc.

FIG. 4 shows a side view of the junction box according to the presentinvention. In this view one is able to see, that parts of the internalcontact elements or solder tails 7 extend over surface of the flange 19or bottom wall 14. Hence said parts extend from the interior space 10over said surface to the external side or exterior space. If thejunction box is mounted onto a solar panel, said parts will be connectedto the solar cell, preferably via a soldered connection. Alternatively awelded or crimped connection is also thinkable. The solder tails extendwith a measure D from the outer surface of the bottom wall 14. Themeasure D is preferably equal to or larger than the thickness of a glasspane of a solar panel, so that the solder tails 7 are able to penetratethrough a hole from one side of said glass pane to the other side ofsaid glass pane. Preferably D is between 1 mm and 10 mm. In otherembodiments D is between 3 mm to 5 mm.

FIGS. 5 a and 5 b show the lid 2 from the front side (FIG. 5 a) and fromthe back side (FIG. 5 b). Said lid 2 has a shape that is substantiallycongruent with the surface of the top wall 13.

On the bottom surface 2 a which faces the top wall 13 of the housing 1when being mounted thereto, the lid comprises a first wall 20. Saidfirst wall 20 extends substantially perpendicular from the bottomsurface 2 a. The wall 20 has a shape that is designed such that it fitsaround the outside of the opening 16 in the top wall 13. The wall 20 andthe first sidewall 11 are designed such that there is a gap between thewall 20 and the first sidewall 11 of the opening 10. Said gap allowsfilling material to flow out as described hereinafter. In alternativeembodiments the wall 20 is designed such that it fits into the opening16 in the top wall 13. Also in that embodiment the wall 20 and the firstsidewall 11 are designed such that there is a gap between the two ofthem. In the present embodiment the wall 20 is designed as a closedloop. However, the wall 20 can also be designed as having severalsections with interruptions.

Additionally the lid comprises further embossments 21. Said embossments21 extend also substantially perpendicular to the bottom surface 2 a,The embossments 21 are arranged within the wall 20. Preferably theembossments 21 have a larger height than the wall 20.

Also on the bottom surface 2 a there is arranged a second wall 22 thatsurrounds the first wall 21. As the first wall 20 and the embossment 21said second wall 22 extends also perpendicular to the bottom surface 2a.

On the top surface 2 b of the lid 2 the lid comprises indicators 23 and24. Such indicators 23, 24 indicate which polarity needs to be contactedto the respective coupling 2, 3.

Preferably the lid 2 is made of plastics. Preferably polycarbonate, forexample Lexan 940-701, is being used to provide the housing. The lid 2is preferably injection molded.

FIGS. 6 a and 6 b show the junction box according to the presentinvention without the lid 2. As it can be seen the top wall 13 comprisesan opening 16. The opening 16 is surrounded by an inner sidewall 171.This inner sidewall 171 extends preferably perpendicular from the topwall 13. Furthermore the opening 16 is fully surrounded by the innersidewall 171. An outer sidewall 170 is arranged around the outerboundary of the top wall 13. Preferably the top wall 13 is fullysurrounded by the outer sidewall 170.

The top wall 13, the outer sidewall 170 and the inner sidewall 171provide a space which can be designated as overflow space 17. Before thelid 2 will be added to the housing 1, the interior space 10 will befully filled with filling material. As the lid 2 will be connected tothe housing 1 some parts of the filling material will overflow from theinterior space 10 to the overflow space 17 due to the embossments 21and/or the first wall 20 that are arranged on the inner surface 2 a ofthe lid 2. As there is a gap between the wall 22 of the lid 2 and thefirst sidewall 11 of the opening 10 filling material can flow throughthat gap as the lid is being pushed into position. Hence the fillingmaterial is forced to flow through the opening 16 in the top wall 13into the overflow space 17. Since the filling material is forced to flowinto the overflow space 17, said filling material is present in theoverflow zone 17 as well as between the inner sidewall 171 and the firstsidewall 20 of the lid 2. Therefore the filling material also acts assealing means between the lid 2 and the housing 1.

FIGS. 7 a and 7 b show the contact elements 5, 6 together with theinternal contact elements 7 and the diode 8. The design of the contactelements 5, 6 is such that they can receive an external female or maleconnector on one end. On the other end the internal contact element herethe solder tail 7 is connected to the contact elements 5, 6.

The internal contact element or solder tail 7 comprises preferably acontact zone 71 through which the solder tail 7 is connected to thefirst contact element 5 or the second contact element 6, respectively. Aresilient zone 72 is arranged adjacent to the contact zone 71. In thepresent embodiment the resilient zone 72 is shaped as an arc. Said arcor the resilient zone 72 can also be designated as bending structure, asthe adjustment of the length of the solder element results in a bendingmotion in the arc. A transfer zone 73 links the resilient zone 72 to theactual solder zone 74. The resilient zone 72 is especially useful toadjust the distance D between the solder zone 74 and the surface of theglass pane of a solar panel assembly in a resilient member. This allowsa filly automatic manufacturing process. The solder zone 74 isconnectable to the solar cell of a solar panel assembly.

FIGS. 8 a and 8 b show the contact elements 5, 6 together with theinternal contact elements 7 and the diode 8 arranged within the firstcoupling 3 and the second coupling 4. Preferably the contact elements 5,6 are arranged within respective coupling 3, 4 and fixed by means of anultrasonic welding process.

FIG. 9 a-9 d illustrate a method for manufacturing a junction boxaccording to the present invention.

The method for manufacturing a junction box according to the presentinvention comprises the steps of:

-   -   providing the first coupling 3 with a first contact element 5        and the second coupling 4 with a second contact element 6; (FIG.        9 a)    -   connecting the first coupling 3 and the second coupling 4 with        the housing 1 (FIG. 9 d).    -   providing each of the contact elements 5, 6 with a solder tail        7; (FIG. 9 b)    -   affixing the diode 8 at the first contact element 5 and at the        second contact element 6; (FIG. 9 c)

The first contact element 5 and the second contact element 6 arepreferably contacted to the first coupling 3 and the second coupling 4by means of an ultrasonic welding or a thermal insertion procedure.However, it is also possible to insert the contact elements 5, 6 into amold in which the plastic is being molded.

The solder tails 7 are preferably welded to the contact elements bymeans of an automatic resistance welding machine. The same applies tothe diode.

The first coupling 3 and the second coupling 4 are connected to thehousing 1 means of an ultrasonic welding procedure.

The result is a pre-assembled junction box that is ready to be connectedto a solar panel. These steps are designed to perform them on a fullyautomatic assembly line, so that the junction box according to presentinvention can be provided in a cost effective manner.

A method for providing a solar panel with a junction box according tothe present invention comprises the steps of:

-   -   Applying adhesive to the junction box base perimeter or flange        19;    -   affixing the junction box on a surface of a solar panel module;    -   affixing solder tail to the contacts of a solar panel;    -   filling the interior space 10 of the housing with a filling        material completely; and    -   mourning the lid 1 on the top wall 13, so that parts 20, 21 of        the lid 2, extend into the interior space 10 of the housing.

The junction box is affixed by means of an adhesive as it is describedabove.

As it can be seen in FIG. 9 d the opening 16 is arranged such thataccess to the solder tails 7 is being provided through the opening 16.Access is provided in a direction substantially perpendicular to thesurface of the solar panel. This means that parts of a robot in anassembly can enter into the interior space 10 through the opening 16 inorder to solder the solder tails 7 to the solder zone of the solar cell.

FIGS. 10 a-10 c show a further embodiment of a junction box according tothe present invention. It is noted that features of this embodiment canbe combined with features of other embodiments and vice-versa to furtherembodiments.

The junction box 1 according to this embodiment comprises sidewalls 11,12 that are designed stiff enough that the placement of ribs in order tostiffen the sidewalls 11, 12 is not necessary. Furthermore the innersidewall 171 that encompasses the opening 16 in the top wall 13comprises snap-in elements 172 for securing the lid 2.

Additionally by means of this embodiment a further embodiment of asolder tail is shown. Said solder tail is designated with referencenumeral 9. However, it has to be noted that such a solder tail 9 whichmay also be designated as solder element or solder tag can be used notonly with the junction box as described herein, but with every otherelectrical device. The same applies to the solder tail 7 as it isdescribed above.

FIGS. 10 b and 10 c show that the solder tail 9 is arranged in the samemanner as in the previous embodiment. Parts of the solder tails 9 extendby a protruding height having a measure D from the outer surface of thebottom wall 14. The measure D is preferably equal to or larger than thethickness of a glass pane of a solar panel, so that the solder tails 9are able to penetrate through a hole from one side of said glass pane tothe other side of said glass pane. Preferably D is between 1 mm and 10mm. In other embodiments D is between 3 mm to 5 mm.

FIGS. 11 a to 11 b show the solder element 9 in a perspective view. Thesolder element 9 preferably comprises a contact zone 91, a resilientzone 92, a transfer zone 93 and a solder zone 94. The solder element 9comprises a middle axis A along which the length of the solder element 9is adjustable. The length is considered to be the distance between thecontact zone 91 and the solder zone 94.

The contact zone 91 is provided to establish an electrical contact witha first electrical device (e.g. the first contact element 5 or secondcontact element 6). Preferably the contact zone 91 is designed such thatit may be connected to the electrical device by means of a solderconnection, welded connection or a crimped connection etc. In thepresent embodiment the contact zone 91 is formed as tubular body 910.Said tubular body 910 comprises a first end having several cut outs 911and a lid portion 912 and a second end on which the resilient zone 92 isformed. However, the contact zone 91 can also be designated as beingcylindrical. The term cylindrical is to be understood as having acircular, rectangular, oval, triangular or elliptical shaped as viewedalong axis A. Furthermore it is possible that the contact zone 91 isformed as a cylinder as defined above and that said cylinder is partlyinterrupted, preferably along the longitudinal axis. The interruptionresults in a gap in the cylindrical body. It is also possible thatinstead of the interruption the parts of the cylindrical or tubular bodyoverlap each other. The lid portion is welded to the connectors 5, 6 andprovides an electrical connection between the connectors 5, 6 and solderelement 9 or the solar panel, respectively.

The resilient zone or compliant zone 92 comprises at least one, herefour, resilient or compliant webs 920. The resilient webs 920 aredesigned such that they are deformable in order to adjust the length ofthe solder element 9, i.e. the distance between the contact zone 91 andthe solder zone 94. Said resilient webs are also designed as a bendingstructure, as the adjustment of the length of the solder element 9results in a bending motion to parts of the web 920. In the presentembodiment the resilient webs 920 comprises an upper section 921 and alower section 922. The upper section 921 is connected to the tubularbody 910 and extends angular with respect to the middle axis A. In thepresent embodiment the upper section 921 extends such that the distancebetween the middle axis A and the web 920 increases with increasinglength of the upper section 921. The lower section 922 is connected tothe upper section 921 and extends contrary to the upper section 921.This means for the present embodiment that the distance between middleaxis A and the web 920 decreases with increasing length of the lowersection 922. This leads to a structure in which the webs 920 extendsover a virtual circumference that is defined by the tubular body ifviewed along the axis A.

In other embodiments of a solder element or solder tail 9 it is alsopossible to provide a resilient zone 92 having a different structure.For example it is possible that the upper section 921 is arranged suchthat the distance between the upper section 921 and the axis A decreaseswith increasing length of the web 920. This means that the web extendsinto the interior of that virtual circumference that is defined by thetubular body.

The webs 920 of the resilient zone 92 are connected to the transfer zone93 which is also designed as a tubular body 931. Preferably the transferzone 93 has the same diameter as the contact zone 91. However, thediameter can also be larger or smaller than the diameter of the contactzone 91. However, the transfer zone 93 can also be designated as beingcylindrical. The term cylindrical is to be understood as having acircular, rectangular, oval, triangular or elliptical shaped as viewedalong axis A. The transfer zone 93 that is formed as a cylinder asdefined above may be partly interrupted, preferably along thelongitudinal axis. The interruption results in a gap in the cylindricalbody. It is also possible that instead of the interruption the parts ofthe cylindrical or tubular body overlap each other.

The solder zone 94 is provided to establish an electrical contact with asecond electrical device (e.g. a solar panel). Said solder zone 94extends from the transfer zone 93. In the present embodiment there isone solder zone 94 arranged but in other embodiments it is also possibleto arranged more than one solder zone 94. The solder zone 94 hereextends angular from the tubular body of the transfer zone 93.

FIG. 11 c shows the solder element 9 according to the present inventionin a normal non-compressed state, whereas FIG. 11 d shows the solderelement 9 in a compressed state. The length of the solder element 9 inthe normal non-compressed state is designated with L1. The elongation ofthe solder element 9 can be positive or negative. Positive elongationresults in a length that is larger than length L1, whereas negativeelongation results in a length that is shorter than length L1. Negativeelongation is shown in FIG. 11 d, whereas the length of the solderelement 9 is designated with L2. Due to the design of the compliantsection 92, the solder element 9 does not return from a compressed stateinto the non-compressed state as soon as the force F disappears.However, in other embodiments where the compliant section 92 isresilient the solder element 9 does return from a compressed state intothe non-compressed state.

Preferably the solder element 9 is made of copper, which allowscompliant and permanent deformation. In other embodiments brass, bronzeor aluminium may also be used.

Usually the force F is built up during a mounting process. To give anexample: If the solder element 9 according to the present invention isused in a junction box to provide a connection between photovoltaicsolar panels, the force F is provided by a mounting tool which crushesthe solder element 9. The length L2 of the solder element after that issuch that the solder section 94 can be connected to the solar panel.

FIGS. 12 a and 12 b show a weather cover 120 which can also bedesignated as a junction box having a lid 121 and a base plate 124. Thefeatures of this embodiment can be combined with the features of theembodiment as disclosed herein. The base plate 124 provides an interiorspace for connector strips 123 which are connected to a solar panel (notshown) on the one hand and to a cable 125 via strain relieves 122 on theother hand. The base plate 124 comprises a flat bottom surface to beconnected to a solar panel by means of an adhesive or a tape. Preferablythe lid 121 and the base plate 124 are made of a rigid polymericmaterial.

The lid 121 is to be arranged onto the base plate 124. Preferably thelid 121 is connected to the base plate 124 via a snap-fit. For thereason the lid 121 and the base plate 124 comprises protrusion whichprovide the snap-fit. The snap-fit also provides a sealed connectionbetween the base plate 124 and the lid 121. Furthermore it is possibleto fill in the interior space with a filling material as disclosedabove.

With such an assembly according to FIGS. 12 a und 12 b it is possible toprovide a weather cover tor connecting a first solar panel with a secondsolar panel.

LIST OF REFERENCE NUMERALS

-   1 housing-   2 lid-   3 first coupling-   4 second coupling-   5 first contact element-   6 second contact element-   7 solder tail-   8 diode-   9 solder tail, solder element-   10 interior space-   11 first sidewall-   12 second sidewall-   13 top wall-   14 bottom wall-   15 bottom opening-   16 opening-   17 overflow space-   18 ribs-   19 flange-   20 first wall-   21 embossments-   22 second wall-   71 contact zone-   72 resilient zone-   73 transfer zone-   74 solder zone-   91 contact zone-   92 resilient zone, compliant zone-   93 transfer zone-   94 solder zone-   120 weather cover-   121 lid-   122 strain relieves-   123 connector strips-   124 base plate-   125 cable-   170 outer sidewall-   171 inner sidewall-   172 snap-in elements-   910 tubular body-   911 cut out-   912 lid-   920 compliant web-   921 upper section-   922 lower section

1. Junction box for a solar panel comprising a housing comprisingsidewalls and a top wall defining an interior space, a lid, a pluralityof internal contact elements which are arranged at least partially insaid interior space, a first coupling comprising a first contactelement, and a second coupling comprising a second contact element,wherein one of said internal contact elements is an electrical contactwith said first contact element and one of said internal contactelements is an electrical contact with said second contact element,wherein said internal contact elements penetrate at least one of thesidewalls, so that the contact elements provide an electrical contactfrom external contact elements to internal contact elements, such assolder tails, wherein the top wall comprises an opening extending onlypartially in said top wall, said opening located in said top wall suchthat access to said internal contact elements in a substantiallyperpendicular direction to the surface of a solar panel for connectingthe internal contact elements to the solar panel is provided and whereinthe first coupling extends along a first axis and the second couplingextends along a second axis, wherein a first external contact element isintroducible into the first coupling along the first axis and a secondexternal contact element is introducible into the second coupling alongthe second axis and wherein the first axis and the second axis arearranged such that they are angular with an angle in a common plane thatis preferably parallel to the bottom wall.
 2. Junction box according toclaim 1, wherein the top wall comprises an outer sidewall that extendssubstantially perpendicular from the top wall and that surroundssubstantially the outer circumference of the top wall, so that anoverflow space is defined by the top wall and the outer sidewall. 3.Junction box according to claim 1, wherein the opening is substantiallysurrounded by an inner sidewall which extends substantiallyperpendicular from said top wall.
 4. Junction box according to claim 1,wherein a filling material is injectable into the interior space throughsaid opening, so that the interior space is fully filled with saidfilling material, and in that the opening is closeable with the lid. 5.Junction box according to claim 1, wherein the lid comprises a wallextending substantially perpendicular to the lid and having a shape thatfits into or around the opening in the top surface.
 6. Junction boxaccording to claim 1, wherein the lid comprises further embossments thatare arranged such that they extend through the opening into the interiorspace when being mounted onto the housing, wherein due to said furtherembossments filling material is forced to flow through the opening intothe overflow space, when said lid is mounted onto the housing filledwith the filling material.
 7. Junction box according to claim 1, whereinthe first coupling and the second coupling are connected to sidewalls,wherein the sidewalls comprise holes in order to allow the contactelement to extend into the interior space.
 8. Junction box according toclaim 1, wherein said angle is between 5° and 170°, in particularbetween 75° and 125°.
 9. Junction box according to claim 1, whereinparts of the solder tail extend from the interior space through a bottomopening in the bottom wall over the surface of the bottom wall. 10.Junction box according to claim 1, wherein the solder tail comprises aresilient section, so that the parts of the solder tail that extend overthe bottom side are moveable with respect to the bottom side. 11.Junction box according to claim 1, wherein the contact element of thefirst coupling is connected with a diode to the contact element of thesecond coupling, wherein the diode is arranged such that the diode iscovered by parts of the top wall.
 12. Method for manufacturing ajunction box according to one of the claim 1, wherein the methodcomprises the steps of providing the first coupling with a first contactelement and the second coupling with a second contact element;connecting the first coupling and the second coupling with the housing;providing each of the contact elements with a solder tail; affixing thediode at the first contact element and at the second contact element.13. Method for providing a solar panel with a junction box according toclaim 1, wherein the method comprises the steps of: applying adhesive tothe junction box base perimeter or flange; arranging the junction box ona surface of a solar panel module; affixing solder tail to the contactsof a solar panel, preferably in perpendicular direction; filling theinterior space of the housing with a filling material, preferablycompletely; and mounting the lid on the top wall, so that parts of thelid, extend to the interior space of the housing.
 14. Photovoltaic solarpanel comprising at least a carrier layer and a solar cell that isarranged on the front side of said carrier layer, wherein a junction boxaccording to claim 1, is arranged on the back side of said carrierlayer.
 15. Photovoltaic solar panel according to claim 14, wherein thebottom side the junction box faces the back side of said carrier layerand in that the carrier layer comprises openings through which thesolder elements are passed through to the solar cell.
 16. Solder elementfor providing an electrical connection between a first electrical deviceand a second electrical device, wherein the solder element comprises acylindrically shaped contact zone to be contacted to the firstelectrical device, a resilient zone and a cylindrically shaped transferzone having a solder zone to be contacted to the second electricaldevice, wherein the axes of the contact zone and of the transfer zoneare axially arranged in alignment of a longitudinal axis and wherein theresilient zone enables adjustment of the axial distance between thecontact zone and the solder zone.
 17. Solder element according to claim16, wherein the resilient zone is arranged between the contact zone andthe solder zone.
 18. Solder element according to claim 16, wherein theresilient zone is designed as a bending structure, wherein bending ofsaid bending structure results in said adjustment.
 19. Solder elementaccording to claim 16, wherein the resilient section comprises at leastone, preferably at least two, even more preferably at least three tosix, resilient web.
 20. Method for producing a solder element accordingto one of the claims 16, wherein the solder element is produced by astamping and/or forming process.
 21. Junction box according to claim 1,wherein said lid is arranged to cover at least said opening.